What is the recommended dose of Phesgo (pertuzumab, trastuzumab, and hyaluronidase-zzxf) and Docetaxel for metastatic breast cancer?

From the Guidelines

For metastatic breast cancer, the standard dosing of Phesgo (pertuzumab/trastuzumab) with docetaxel is as follows: Phesgo is given as an initial loading dose of 1,200 mg pertuzumab/600 mg trastuzumab subcutaneously, followed by maintenance doses of 600 mg pertuzumab/600 mg trastuzumab every 3 weeks. Docetaxel is typically administered at 75-100 mg/m² intravenously every 3 weeks for at least 6 cycles, though it can be discontinued earlier if toxicity becomes unmanageable. After completing docetaxel, Phesgo is continued until disease progression or unacceptable toxicity. This regimen is specifically for HER2-positive metastatic breast cancer patients. Before starting treatment, cardiac function should be assessed with baseline LVEF measurement, and regular monitoring should continue throughout therapy. Common side effects include infusion-related reactions, neutropenia, diarrhea, and potential cardiotoxicity. Dose adjustments may be necessary based on individual patient factors such as liver function, prior treatments, and tolerability, as recommended by the NCCN panel 1.

Some key points to consider when administering Phesgo with docetaxel include:

• The combination of pertuzumab and trastuzumab has been shown to improve progression-free survival and overall survival in patients with HER2-positive metastatic breast cancer 1.
• The NCCN panel recommends pertuzumab plus trastuzumab in combination with a taxane as a preferred option for first-line treatment of patients with HER2-positive metastatic breast cancer 1.
• Health-related quality of life was maintained for a longer duration with the combination of pertuzumab and trastuzumab compared with trastuzumab and a taxane alone 1.
• The optimal sequence of available HER2-targeted therapies and the optimal duration of HER2-targeted therapy for recurrent/stage IV is currently unknown, but the NCCN panel recommends continuing HER2-targeted therapy until progression or unacceptable toxicity 1.

It is essential to carefully evaluate each patient's individual factors and adjust the treatment plan accordingly to minimize toxicity and maximize efficacy, as supported by the evidence from the NCCN guidelines 1.

From the FDA Drug Label

For metastatic breast cancer, the recommended initial dose of docetaxel is 75 mg/m2 administered as an intravenous infusion. The dose may be escalated to 100 mg/m2 administered every 3 weeks if the initial dose is well tolerated.

• The recommended dose of docetaxel for metastatic breast cancer is 75 mg/m2 to 100 mg/m2 administered intravenously every 3 weeks 2.
• The dose may be escalated to 100 mg/m2 if the initial dose is well tolerated.

From the Research

Dosage of Phesgo and Docetaxel for Metastatic Breast Cancer

• The studies provided do not directly mention the dosage of Phesgo and Docetaxel for metastatic breast cancer.
• However, the studies discuss the treatment options for HER2-positive metastatic breast cancer, including the combination of trastuzumab, pertuzumab, and a taxane (such as docetaxel) as the preferred first-line therapy 3, 4.
• The dosage of docetaxel is not specified in the provided studies, but it is mentioned that pertuzumab can be effectively combined with docetaxel and trastuzumab in patients with metastatic HER2-positive breast cancer 4.
• Phesgo is not mentioned in the provided studies, but it is a fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injection, which may be used in combination with docetaxel for the treatment of HER2-positive metastatic breast cancer.

Treatment Options for Metastatic Breast Cancer

• The current standard first-line therapy for patients with HER2+ metastatic breast cancer is a taxane combined with trastuzumab and pertuzumab 3, 5.
• Trastuzumab deruxtecan should be used preferentially in the second line, with the only caveat being patients with CNS involvement where the tucatinib, capecitabine, and trastuzumab regimen could be considered 5.
• In the third line setting, given the survival benefits demonstrated with the tucatinib regimen in patients with and without CNS metastases, this is the preferred strategy 5.
• There are several novel therapies under investigation reporting promising results in the late-line setting, including margetuximab in combination with chemotherapy, neratinib + capecitabine, or trastuzumab + chemotherapy 5.